Excessive use of candles and tea lightsFogging is understood as ghosting black dust deposits, which can partly occur overnight in apartments. The oily, greasy deposits on walls and furniture can only be cleaned with great effort. Diploma chemist Martin Wesselmann from Hamburg sees a gender-specific problem group among those affected. In 62% of the households surveyed by Wesselmann lived women and in 33% couples or families. Only 5% were pure male households. The excessive use of candles and tea lights is the main cause of black dust. The gender-specific allocation of causes is based on 132 dwellings.
Decrease of nicotine and plasticizers
Martin Besselmann compares the study series from 2006 with those from the year 2016. Noticeable is a strong decline of nicotine and plasticizers (phthalates). The paraffins remained almost constant. The examination of wipes proves demonstrably conclusions about the use of candles and tealights in the dug-out dwellings. Although paraffins also occur in wall paints and surface coatings of furniture, a connection with fogging can not be proved. Because then far more apartments would have problems with black dust deposits. Besselmann has also found intensive and frequent use of personal care and cleaning products in households. Tealights were often used together with incense sticks and aromatic oils.
It comes to fogging relevant particle sizes
By combustion processes of candles and tea lights, ultra-fine particles with a size of less than a hundred nanometers are formed. These fine particles clump into larger units and spread through air streams in the rooms. Finally, particle sizes of two to three micrometers (PM2.5) were found on the black walls. The accompanying publications for the deposits have not yet been fully clarified. An important role is played by differently tempered rooms and differently high surface temperatures of the walls and ceilings. The temperature differences occur when rooms are not heated uniformly or when a room cools down due to tilted windows in the winter. Cold surface temperatures are caused, for example, by poor thermal insulation in old buildings. Partially black dust deposits are found over radiators. There is then the presumption that in these cases the flow temperature is too high.
Martin Wesselmann: “The phenomenon of the black dwellings” in the AGÖF-Tagungsband 2016, ISBN 978-3-930576-10-4
Zwiener / Mötzl: Ecological Building Materials Dictionary. Publisher C.F. miller
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